In recent years, attention has been given to display devices in which a touch detection device referred to as a so-called touch panel is provided on a display device such as a liquid crystal display device, or a touch panel and a display device are integrated as a single body, and the display device is made to display various button images to enable information to be input without ordinary real buttons. Such display devices having a touch detection function do not need input devices such as a keyboard, a mouse and a keypad, and thus tend to be broadly used as display devices of computers, portable information terminals such as cell phones, etc.
As such a touch panel, a capacitive touch panel is known in which a plurality of electrodes each formed to extend in a single direction are intersected to each other. In this touch panel, the electrodes are connected to a control circuit, and when supplied with an excitation current from the control circuit, they detect an external object close thereto.
As a display device having touch detection function, a so-called in-cell touch panel is proposed in addition to a so-called on-cell touch panel in which a touch panel is provided on a display surface of a display device. In the in-cell display device, a common electrode for display, which is originally provided in the display device, is also used as one of a pair of electrodes for a touch sensor, and the other of the pair of electrodes (a touch detection electrode) is provided to intersect the common electrode.
Furthermore, a touch detection device is disclosed in which drive electrodes for touch sensor are successively selected in a time sharing manner such that a predetermined number of drive electrodes for touch sensor are selected at a time, and a touch detection signal is supplied to the selected drive electrodes for touch sensor, and scanning drive is performed such that a scanning pitch is smaller than a total width of the selected target drive electrodes (this scanning drive will be hereinafter referred to as “bundle drive”).
It should be noted that since the above bundle drive needs to be synchronized with the display operation, in the touch detection device, a touch driver (TPIC) which controls a touch drive operation and a display driver (DDI) which controls a display operation perform a touch drive control in cooperation with each other. Thus, the display driver is configured to have a patterned touch drive control function.
However, in the case where identical display drivers are applied to various display panels, there is a case where the patterned touch drive control function needs to be changed in order to optimize a display operation and a touch drive operation.